81100406 has 4 divisors (see below), whose sum is σ = 121650612. Its totient is φ = 40550202.

The previous prime is 81100399. The next prime is 81100447. The reversal of 81100406 is 60400118.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 60400118 = 2 ⋅30200059.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 20275100 + ... + 20275103.

It is an arithmetic number, because the mean of its divisors is an integer number (30412653).

Almost surely, 2^81100406 is an apocalyptic number.

81100406 is a deficient number, since it is larger than the sum of its proper divisors (40550206).

81100406 is a wasteful number, since it uses less digits than its factorization.

81100406 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40550205.

The product of its (nonzero) digits is 192, while the sum is 20.

The square root of 81100406 is about 9005.5763835526. The cubic root of 81100406 is about 432.8535756808.

The spelling of 81100406 in words is "eighty-one million, one hundred thousand, four hundred six".